You are aiming the structure
Since the predicate outside of factorization is もらう, the surface subject of it is 私 rather than あなた.
Now, consider the role of 私 in the two verb phrases that are conjoined.
In the first conjunct, the role of 私 is the benefactee. In the second, it is the embedded (dative) subject of a causative construction. Since these phrases are also the surface subject of the common predicate もらう, they have to move out (factorize, in your terminology). However, it is known that language does not allow factorization of an item from different structural positions in conjoined elements. Technically, this is known as Across the Board Generalization exception to The Coordinate Structure Constraint. That is the reason it will not work.
Now, let us consider what you can do instead. The problem arose from trying to move 私. Instead of doing movement, you can leave them implicit and move the common subject of the two conjuncts: あなた. Then, あなた will occupy the surface subject position of the predicate outside, so the predicate will now have to be the one that fits in meaning with having あなた as the subject. That is くれる. Hence you get the grammatical sentence: